Electrical terminal and method of applying same to conductors



ONDUCTORS H. A. ELLIOTT Aug. 9, 1966 ELECTRICAL TERMINAL AND METHOD OF APPLYING SAME TO C Filed Jan. 13, 1964 3,266,008 ELECTRICAL TERMINAL AND METHGI) F APPLYING SAME T0 CONDUCTORS Howard A. Elliott, Detroit, Mich, assignor to Essex Wire Corporation, Fort Wayne," Ind, a corporation of Michigan I Filed Jan. 13, 1964, Ser. No. 337,291 2 Claims. (Cl. 339-223) This invention relates .to electrical terminals and to a method for applying them to electrical conductors, and it particularly relates to electrical terminations for nonmetallic core conductors and to methods for terminating such conductors.

Today, non-metallic c-ore cables, asstranded glass core cables, are commonly utilized for many applications, and they are frequently used as automotive ignition cables orthe like. When a non-metallic or glass core conductor is terminating .in a manner similar to that shown in my ear'lier'U.S. Patent No. 2,553,083, that is, by folding the projecting end of the conductor against the outer surface of the insulation before mounting a terminal on the cable, it is often difficult to obtain a good electricalcontact or connection between .the terminal .and the non-metallic conductor. Specifically, due to the poor electrical connection, sparking often occurs between the non-metallic conducting core and the electrical terminal or connector.

Thus, it is an important'obje'ct of this invention to provide an electrical connection between a non-metallic conductor and an electrical terminal wherein disadvantages of such previous terminations are substantiallyavoided.

' Itis'also an object of this invention to .providean improved electrical termination for a stranded non-metallic conductor by applying an electrically conductive medium to the projecting end of the conductor, prior to folding the projecting end of the conductor against the insulation and mounting the electrical terminal member on the cable.

It is a further object of this invention to provide a method for terminating a glass core conductor, wherein a superior electrical connection is provided between the glass core and the terminal which is mounted on the cable.

It is another object of this invention to provide a method for terminating a stranded glass core electrical conductor wherein a conductive medium, having carbon particles therein, is applied to the projecting portion of a stranded glass conductor to provide a unitary bundle of strands, after which the end of the conductor is folded against the insulation and an electrical terminal is mounted thereon.

It is still 'anotiher'object of this invention to provide an improved electrical termination for a glass core conductor, wherein the method is characterized by its simplicity and economy.

Further purposes and objects of this invention will appear as the specification proceeds.

Particular embodiments of the present invention are illustrated in the accompanying drawings wherein:

FIGURE 1 is a plan view of a glass core conductor;

FIGURE 2 is a view similar to FIGURE 1, except that an electrically conductive medium has been applied to the stranded end of the glass core;

United States Patent 0 3,266,068 Patented August 9, 1966 ice FIGURE 7 is a sectional view, taken along the line 7-7 of FIGURE 6;

FIGURE 8 is a sectional view through my improved electrical termination, when utilizing a molded type electrical terminal; and

FIGURE 9 is a sectional view taken along the line 9- -9 of FIGURE 8.

Referring to the drawings, there is shown an electrical cable 10 having insulation 12 surrounding a non-metallic conductor 14. The conductor 14 is comprised of a multiplicity of electrically conductive fibers or strands; advantageously, the conductor 14 is glass, but may also be made of other conductive materials, as linen, rayon, etc. Due to the physical properties of the conductor 14, it is difficu-lt to provide a good electrical connection between an electrical terminal or connector 16 and the conductor 14, particularly when using the type of electrical connection shown in FIGURE 3.

In FIGURE 3, the conductor 14 is .folded against the insulation 12 and a terminal 16 is crimped or mounted on the insulation 12 to thereby provide electrical connection between the conductor 14 and the terminal 16. In order to provide a proper connection between the terminal 16 and the glass conductor 14, the stranded end of the conductor 14 is treated with a flu-id medium having electrical conductive properties. This medium notonly conducts electrical current but is adapted to adhesively bind the fibers or strands of the conductor 14 together, whereby as'the terminal leis crimped to the insulation 12, one or both of the attaching fingers 18 of the terminal 16 are adapted toencompass the bundle of strands, 'as shown in FIGURE 4; this connectionprovides a good electrical contact between the conductor 14 and the terminal 16.

Referring to FIGURES 57, my electrical termination is shown with an alternate type of electrical terminal 2 8. The terminal 28 is of the straight type, rather than of the elbow type of FIGURES 3 and 4. Again, with the terminal 28, the conductive, adhesive medium is appliedto the projectingstrands of the conductor '14 prior to mounting the terminal 23 to the cable '10, while trapping the conductor 14 between the barre-l30 and the insulation 12.

With reference to FIGURES 8 and 9, there is shown another alternate type of terminal 20, which is provided with molded insulation 26. Generally, the terminal 20 includes a conductor receiving leg 22 and an electrode receiving leg 24. The insulation 26 surrounds the metallic legs 22 and 24 to thus provide an insulated terminal. As with the previously described embodiments, the projecting end of the glass conductor is folded against the insulation after receiving an application of the conductive medium. Since there is a problem of the insulation material 26 flowing between the terminal 20 and the cab-1e insulation 12 during the molding operation, the terminal 20 also receives a coating of the conductive medium prior to mounting it to the cable 10; thus, when the insulation 26 is molded in place, a good electrical connection is maintained, thereby substantially avoiding a disturbance of the connection between the terminal 20 and the conductor 14.

Although my method for providing an improved electrical termination should be clear from the foregoing, briefly in providing the termination of FIGURES 3-7, the insulation 12 is first stripped from the end of the cable 10 to thereby provide a projecting portion of a stranded conductor 14. The projecting end of the conductor 14 is then treated with a conductive medium or paste. Desirably, the medium is a dispersion of carbon particles in a resinous base; the material is adapted to bind the strands of the conductor 14 together to provide a unitary bundle which have been found to be satisfactory are a dispersion of graphite in an alkyd resin-naphtha vehicle, a dispersion of graphite in an epoxy resin solution, and a dispersion of graphite in ethyl alcohol. Following the application of the conductive paste or medium to the glass core 14, it is folded against the outer surface of the insulation 12; the electrical terminal is then applied to the cable 10, by utilizing conventional procedures, as crimping, before the paste is allowed to dry.

If the embodiment of FIGURES 8 and 9 is utilized, the same type of conductive paste is applied to the terminal 20 and is dried before the terminal 20 is crimped to the insulation, trapping the glass core against the insu- *lation. The application of the conductive paste to the terminal 20 prevents the sleeve insulating material 26 from flowing between the terminal and the cable insulation, which would be likely to disturb the connection be tween the core 14 and the terminal 20. Other than the application of the conductive paste to the terminal 20, followed by drying, the terminating procedure is substantially the same as the above-discussed procedure.

My improved termination thus provides excellent electrical connection between an electrical terminal and a nonmetallic conductor; the connection provided substantially prevents sparking between the cable and the terminal. Furthermore, the termination is durable and utilizes simple and economical manufacturing procedures.

While in the foregoing, there has been provided a detailed description of particular embodiments of the present invention, it is to be understood that all equivalents obvious to those having skill in the art are to be included within the scope of the invention as claimed.

What I claim and desire to secure by Letters Patent is:

1. The method of making an electrical connection to an ignition cable, having an outer sheath of electrical insulation material and an inner core of non-metallic fibrous strands coated with an electrically conductive carbonaceous material comprising the steps of:

removing a portion of said sheath from one end of said cable to bare an end portion of said core;

applying to said end bared portion of said core a conductive medium comprising a dispersion of carbon particles in a resinous base;

folding said end portion of the core over said one end of the sheath after application of said conductive medium;

forming an electrical terminal with a tubular ferrule portion of sheet metal;

placing said ferrule portion around said one end of said sheath and said end portion of said core such that said end portion is sandwiched between said sheath and said ferrule portion of said terminal; and

tightly crimping said ferrule portion around said sheath and said folded end portion of the core to produce a secure conductive connection between said terminal and said core.

2. In combination,

an ignition cable having an outer sheath of electrical insulation material and an inner core of non-metallic fibrous strands coated with an electrically conductive carbonaceous material; said core having an end portion thereof extending beyond one end of said sheath and, folded over said one end of said sheath;

said end portion of said core being impregnated with a conductive medium comprising a dispersion of carbon particles in a resinous base for binding the strands of said end portion of said core together, and

an electrical terminal having a ferrule portion of sheet metal extending around and tightly crimped onto said end of said sheath and the impregnated end portion of said core with said ferrule portion in electrically conductive engagement with said impregnated core.

References Cited by the Examiner UNITED STATES PATENTS 1,394,055 10/1921 White 338332 1,946,713 2/ 1934 Rowley 339-223 2,423,290 7/ 1947 Bonwitt 3391 15 2,714,623 8/1955 Wolcott 174120 2,745,075 5/1956 Simpkins et al 339-26 2,869,103 1/1959 Wells 339 3,109,881 11/1963 Publow 174121 X FOREIGN PATENTS 239,216 12/ 1926 Great Britain. 440,762 12/ 1936 Great Britain.

EDWARD C. ALLEN, Primary Examiner.

Disclaimer 3,266,008.[]01007'(i A. Elliott, Detroit, Blich. ELECTRICAL TERMINAL AND METHOD OF APPLYING SAME TO CONDUCTORS. Patent dated Aug. 9, 1966. Disclaimer filed June 20, 1974, by the assignee, Essex I nternational, Inc. Hereby enters this disclaimer to claim 2 of said patent.

[Ojficz'al Gazette May 20, 1.975.] 

2. IN COMBINATION, AN IGNITION CABLE HAVING AN OUTER SHEATH OF ELECTRICAL INSULATION MATERIAL AND AN INNER CORE OF NON-METALLIC FIBROUS STRANDS COATED WITH AN ELECTRICALLY CONDUCTIVE CARBONACEOUS MATERIAL; SAID CORE HAVING AN END PORTION THEREOF EXTENDING BEYOND ONE END OF SAID SHEATH AND FOLDED OVER SAID ONE END OF SAID SHEATH; SAID END PORTION OF SAID CORE BEING IMPREGNATED WITH A CONDUCTIVE MEDIUM COMPRISING A DISPERSION OF CARBON PARTICLES IN A RESINOUS BASE FOR BINDING THE STRANDS OF SAID END PORTION OF SAID CORE TOGETHER, AND AN ELECTRICAL TERMINAL HAVING A FERRULE PORTION OF SHEET METAL EXTENDING AROUND AND TIGHTLY CRIMPED ONTO SAID END OF SAID SHEATH AND THE IMPREGNATED END PORTION OF SAID CORE WITH SAID FERRULE PORTION IN ELECTRICALLY CONDUCTIVE ENGAGEMENT WITH SAID IMPREGNATED CORE. 